This book was the basis of an 8 episode TV sitcom made for the BBC in 1977, which was co-written by Barry Took and starred Brian Rix. I can only speculate about the title – was it always intended to be a Coarse book? Why did it take 8 years to make it to the small screen? The book’s narrative is in the form diary entries and there is no mention of the “Coarse” word.
The later paperback swapped the title around, and that looks like Ron Tarr (Big Ron from Eastenders) on the cover to me.